package edu.suda.basic.security;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;


public class FileEncDec
{
	// static boolean debug =false ;
	// 加密KEY不能随便改动
	static final byte[] KEYVALUE = "6^)(9-p35@%3#4S!4S0)$Y%%^&5(j.&^&o(*0)$Y%!#O@*GpG@=+@j.&6^)(0-=+".getBytes();
	static final int BUFFERLEN = 512;

	public FileEncDec()
	{
	}

	/**
	 * 对文件进行加密
	 * @param String oldFile 原始要加密的文件
	 * @param String newFile 加密后的文件
	 * @return
	 */
	public static void encryptFile(String oldFile, String newFile) throws Exception
	{
		FileInputStream in = new FileInputStream(oldFile);
		File file = new File(newFile);
		if (!file.exists())
			file.createNewFile();
		FileOutputStream out = new FileOutputStream(file);
		int c, pos, keylen;
		pos = 0;
		keylen = KEYVALUE.length;
		byte buffer[] = new byte[BUFFERLEN];
		while ((c = in.read(buffer)) != -1)
		{
			for (int i = 0; i < c; i++)
			{
				buffer[i] ^= KEYVALUE[pos];
				out.write(buffer[i]);
				pos++;
				if (pos == keylen)
					pos = 0;
			}
		}
		in.close();
		out.close();
	}

	/**
	 * 对文件进行解密
	 * 
	 * @param String oldFile 原始要解密的文件
	 * @param String newFile 解密后的文件
	 * @return
	 */
	public static void decryptFile(String oldFile, String newFile) throws Exception
	{
		FileInputStream in = new FileInputStream(oldFile);
		File file = new File(newFile);
		if (!file.exists())
			file.createNewFile();
		FileOutputStream out = new FileOutputStream(file);
		int c, pos, keylen;
		pos = 0;
		keylen = KEYVALUE.length;
		byte buffer[] = new byte[BUFFERLEN];
		while ((c = in.read(buffer)) != -1)
		{
			for (int i = 0; i < c; i++)
			{
				buffer[i] ^= KEYVALUE[pos];
				out.write(buffer[i]);
				pos++;
				if (pos == keylen)
					pos = 0;
			}
		}
		in.close();
		out.close();
	}

	/**
	 * @param args
	 */
//	public static void main(String[] args)
//	{
//
//		try
//		{
//			// debug =false ;
//			String oldFile = new String("C:\\aa.txt");
//			String newFile = new String("C:\\aa_en.txt");
//			String newnewFile=new String("C:\\aa_de.txt");
//			//encryptFile(oldFile, newFile);
//			System.out.println("ok");
//			
//			decryptFile(newFile,newnewFile);
//		}
//		catch (Exception e)
//		{
//			e.printStackTrace();
//		}
//	}
}